I have a few thoughts about the general decline in traffic.
I believe a forum oriented message board will always maintain some exponential levels of participation when it comes to the membership. There are people who register and never create a post, there are people who register post a few times and dissapear, there are people who log in and participate infrequently and there will be members who are active and engaged and interested in shoving their two cents anywhere they can... and all kinds of nuances in between. For every hyperactive participant, there will be exponentially larger numbers who are less active. It also takes a certain number of active members to maintain the interest of the less active ones- some users will not create threads, but might reply to one- fewer active people means fewer inactive people bothering to log in and open a thread. Without login purges done on a regular basis, this only becomes truer over time. That addresses the issue of total membership versus site use but not the specific issue of a decline in site participation when looked at over the last year.
I'd explain the general decline as being primarily a result of schisms. This is not... and I want to be absolutely clear on this... saying that there is blame on either side. I am blaming the catalyst, not the participants. When debates were ongoing about site changes, people drew up sides and, if a decision didn't go the way they wanted it to, some people left. Some left loudly while in the middle of a heated argument, some just quietly wandered away and- this is an important part- given the level of personal investment I was seeing, *someone* was going to be walking away from the sandbox no matter which conclusion was reached because opinions ranged all over the place. When an active members walks away though, they take their participation with them, anything they would have contributed to various discussions, any comment that might have sparked the interest of a less active member and prompted them to reply themselves. So the loss of a person who checks the forums daily and responds regularly takes with it the interest and potential participation of theoretical additional people.
Unfortunately those debates have come more frequently and a few have seen both sides expressed in practice. I'm going to go back a bit longer than a year and throw out a specific example.
The BOI required a member to be a paid (low dollar amount but there it is) participant for awhile. There was debate, there were discussions, there were pessimistic predictions of doom and optimistics predictions of utopia. A decision was reached, a plan implimented and some people decided they no longer wanted to participate based on that policy change. Some more active users stopped using the site (I did, as an example. No animosity, just didn't like the decision and decided myself I wasn't interested for awhile) and stopped contributing. Time passes, the outcome is analyzed and reversed and there's more debate and more argument and some people decide they don't want to participate any more as a result of *that* direction. Some people who stopped or slowed their participation after the first decision hear about the change and come back, but not all of them. Subtract the returners from the new people who aren't participating and the net result is still a loss. So there's an initial negative impact on participation, then a change is mitigated by those who like the switch up, but still has a negative impact on participation... and figure that the loss of those active people can be applied to a general decline in the interest of others who are less active but are now seeing less content they have an interest in...
And apply it to every change in any policy, no matter how minimal the impact on the site itself should have been, about which there was debate and the cummulative result will be a decline.
I'm not saying that some of the threads that have gone harsher lately haven't had some impact, I just think the decline in the numbers that were given over the period of time they covered probably are showing as they are for the above reason, rather than any threads or posts that happened in the last month. Those posts and any resulting enforcement be it harsh or forgiving, may form their own catalyst for some individuals which will be shown over time to have an impact but can't be said to be solely responsible over the time frame covered.
